c++的do while不断重复

#include <iostream>
#include <string>
#include <cctype>
#include <sstream>
using namespace std;
int getTreeNo(int);
int getSpeciesCode(int);
float getDbh(float);
int getTotHt(int);
int getTotHt(int);
double calcTotVol(double[], double[], float, int);
int main() {
    int i = 0;
    int treeNo = 0;
    int speciesCode = 0;
    string speciesDesc[6] = {};
    float dbh = 0.00;
    int totalHt = 0;
    double totalVol = 0.00;
    int Species[6] = {};
    double b0[6] = {};
    double b1[6] = {};
    int noTrees = 0;
    treeNo = getTreeNo(treeNo);
    /* Gets number of trees for calculations*/
    speciesCode = getSpeciesCode(speciesCode);
    /* Get Species code from user*/
    dbh = getDbh(dbh);
    /* get DBH from user*/
    totalHt = getTotHt(totalHt);
    /*Gets tree height from user*/
    totalVol = calcTotVol(b0, b1, dbh, totalHt);
    /* Calculates values */
    /* All constants and variables
        int treeNo;
        int speciesCode;
        string speciesDesc[6];
        float dbh;
        int totalHt;
        double totalVol;
        int Species[6];
        double b0[6];
        double b1[6];
        int noTrees;
        double avgTotVol;
    */
    if (speciesCode = 11) {
        speciesDesc[0] = "Loblolly Pine";
    } else if (speciesCode = 12) {
        speciesDesc[1] = "White Pine";
    } else if (speciesCode = 13) {
        speciesDesc[2] = "Red Pine";
    } else if (speciesCode = 21) {
        speciesDesc[3] = "White Oak";
    } else if (speciesCode = 22) {
        speciesDesc[4] = "Red Oak";
    } else if (speciesCode = 23) {
        speciesDesc[5] = "Other Oak";
    }
    Species[0] = 11;
    Species[1] = 12;
    Species[2] = 13;
    Species[3] = 21;
    Species[4] = 22;
    Species[5] = 23;
    if (speciesCode = 11) {
        b0[0] = 1.2446;
    } else if (speciesCode = 12) {
        b0[1] = 0.000;
    } else if (speciesCode = 13) {
        b0[2] = 2.0822;
    } else if (speciesCode = 21) {
        b0[3] = .7316;
    } else if (speciesCode = 22) {
        b0[4] = 1.6378;
    } else if (speciesCode = 23) {
        b0[5] = .7554;
    }
    if (speciesCode = 11) {
        b1[0] = .002165;
    } else if (speciesCode = 12) {
        b1[1] = .002364;
    } else if (speciesCode = 13) {
        b1[2] = .002046;
    } else if (speciesCode = 21) {
        b1[3] = .001951;
    } else if (speciesCode = 22) {
        b1[4] = .002032;
    } else if (speciesCode = 23) {
        b1[5] = .002174;
    }
    totalVol = b0[6] + b1[6] * pow(dbh, 2) * totalHt;
    for (i = 0; i < treeNo; i++) {
        cout << "Tree Number " << i + 1 << ": " << speciesCode << dbh << totalHt
             << speciesDesc[6] << b0[6] << b1[6] << totalVol;
    }
}
/************************************************************************************************
 * *************/
int getTreeNo(int treeNo) {
    do {
        cout << "Please enter the number of trees :" << endl;
        cin >> treeNo;
        if ((treeNo <= 0) || (treeNo > 999)) {
            cout << "ERROR!!!,You cannot have more then999 entries" << endl;
        }
    } while ((treeNo <= 0) || (treeNo > 999));
    return treeNo;
}
int getSpeciesCode(int speciesCode) {
    do {
        cout << "Please enter your Species Code";
        cin >> speciesCode;
    } while ((speciesCode != 11) || (speciesCode != 12) ||
             (speciesCode != 13) || (speciesCode != 21) ||
             (speciesCode != 22) || (speciesCode != 23));
    cout << "ERROR!!!,That information does not exist wthin our system" << endl;
    return speciesCode;
}
float getDbh(float dbh) {
    do {
        cout << "Please enter the DBH of the tree, The DBH must be greter then "
                "and equal to  five and less then 50.6" << endl;
        cin >> dbh;
        if ((dbh < 5) || (dbh > 50.6)) {
            cout << "ERROR!!!, The DBH must be greter then and equal to five "
                    "and less then 50.6" << endl;
        }
    } while ((dbh < 5) || (dbh > 50.6));
    return dbh;
}
int getTotHt(int totalHt) {
    do {
        cout << "Please enter the height of the tree" << endl;
        cin >> totalHt;
        if ((totalHt < 24) || (totalHt > 160)) {
            cout << "ERROR!!!, Please enter a height thats not larger then "
                    "160, but greater then 24" << endl;
        }
    } while (totalHt < 24 || totalHt > 160);
    { return totalHt; }
}
double calcTotVol(double array[], double array1[], float dbh, int totalHt) {
    double totalVol;
    totalVol = array[6] + array1[6] * pow(dbh, 2) * totalHt;
    return totalVol;
}

谁能帮助我我的speciesCode函数一直循环，不会接受我的输入，实际上我不相信任何函数正在接受它，我已经工作了几个小时，试图找出原因，我卡住了

感谢您的帮助