列主元高斯消元法动态输入

#include <iostream>#include<cmath>#include<vector>using namespace std;int main(){int i,j ,row_count ,column_count;cout<<"输入行数列数：";cout<<endl;cin>>row_count>>column_count;vector<vector<float> > a(row_count, vector<float>(column_count)); for(i=0;i<row_count;i++){for(j=0;j<column_count;j++){cin>>a[i][j];}}float b[1];vector<float> c(column_count);int d[1];for(int e=0;e<row_count-1;e++){b[0]=a[e][e];d[0]=e;for(int k=1+e;k<row_count;k++)//找主元最大行{if(fabs(a[k][0])>fabs(b[0])){b[0]=a[k][0];d[0]=k;}}if(b[0]==0)//判断矩阵是否是奇异矩阵{cout<<"矩阵是奇异的";return 0;}if(d[0]!=e)//交换上下行的值{for(int l=e;l<column_count;l++){c[l]=a[e][l];a[e][l]=a[d[0]][l];a[d[0]][l]=c[l];}}for(int m=1+e;m<row_count;m++)//列主元消去{c[0]=a[m][e];for(int n=e;n<column_count;n++){a[m][n]=a[m][n]-a[e][n]*c[0]/a[e][e];}}}vector<float> x(row_count);for(int f=0;f<row_count;f++)x[f]=0;float y;int h=row_count-1;for(int index=row_count;index>0;index--){int g=row_count-1;y=a[h][column_count-1];while(x[g]!=0){y=y-a[h][g]*x[g];g--;}x[g]=y/a[g][g];h--;}for(int v=0;v<row_count;v++)cout<<"x["<<v<<"]="<<x[v]<<" ";cout<<endl;return 0;}