int main(int argc, char* argv[])
{
int k = 0;
int n = 0;
int flag = 0;
int** array;
printf("Please input the line and row number of the matrix:\n");
scanf("%d",&n);
//Create matrix
printf("Start create a %d * %d matrix.\n",n,n);
array = (int**)malloc(sizeof(int*)*n);
for(k = 0; k < n; ++k)
{
array[k] = (int*)malloc(sizeof(int)*n);
}
printf("If you want get an identity matrix, please input 0, while if you want an invertible matrix, just input 1.\n");
scanf("%d",&flag);
if(flag == 0)
{
printf("Your input word is %d, so you want an identity matrix:\n",flag);
//get indentity matrix
getIdentityMatrix(n, array);
//put indentity matrix into file
putIdentityMatrixIntoFile(n, array);
//print identity matrix
printIdentityMatrix(n, array);
}
else if(flag == 1)
{
printf("Your input word is %d, so you want an invertible matrix:\n",flag);
//get indentity matrix
getIdentityMatrix(n, array);
//get invertible matrix
getInvertibleMatrix(n, array);
//put invertible matrix into file
putInvertibleMatrixIntoFile(n, array);
//print invertible matrix
printInvertibleMatrix(n, array);
}
else
{
printf("Error: You input a wrong number!\n");
return -1;
}
//free matrix
printf("Free matrix.\n");
freeMatrix(n, array);
return 1;
}注：代码中最后出现的freeMatrix函数是我专门为了释放数组内存写的，代码如下：
void freeMatrix(int n, int** array)
{
int k = 0;
for(k = 0; k < n; ++k)
{
free(array[k]);
}
free(array);
}void getIdentityMatrix(int n, int** array)
{
int r = 0;
int c = 0;
for(r = 0; r < n; ++r)
{
for(c = 0; c < n; ++c)
{
if(r == c)
array[r][c] = 1;
else
array[r][c] = 0;
}
}
}mainRowNum = (int)(rand()%（n-1）);这句话是随机的在矩阵0~n-1行中选择一个主行作初等行变换，第一个循环是将主行中的元素进行一定的处理
array[mainRowNum][k])*((int)(rand()%5 - 10)后存入中介数组tempArray中（处理方式是我随便写的，也可以是别的运算方式）。
((UINT16_MAX - (array[mainRowNum][k])*((int)(rand()%5 - 10))) < 0) || ((UINT16_MAX*(-1)) - (array[mainRowNum][k])*((int)(rand()%5 - 10)) > tempArray[k])则是为了判断采用上述处理方式对矩阵元素进行运算后，元素数值是否会溢出。（如果你想了解更多，请看这里：点击打开链接）
void getInvertibleMatrix(int n, int** array)
{
int i = 0;
int j = 0;
int k = 0;
int mainRowNum = 0;
int* tempArray = NULL;
srand((int)time(NULL));
int transformTime = (int)(rand()%1000);
printf("We will do %d times tansformation.\n",transformTime);
tempArray = (int*)malloc(sizeof(int)*n);
for(i = 0; i < transformTime; ++i)
{
mainRowNum = (int)(rand()%（n-1）);
for(k = 0; k < n; ++k)
if(((UINT16_MAX - (array[mainRowNum][k])*((int)(rand()%5 - 10))) < 0) || ((UINT16_MAX*(-1)) - (array[mainRowNum][k])*((int)(rand()%5 - 10)) > tempArray[k]))
tempArray[k] = (array[mainRowNum][k]);
else
tempArray[k] = (array[mainRowNum][k])*((int)(rand()%5 - 10));
for(j = 0; j < n; ++j)
if(mainRowNum != j)
for(k = 0; k < n; ++k)
{
if(((UINT16_MAX - array[j][k]) < tempArray[k]) || ((UINT16_MAX*(-1)) - array[j][k] > tempArray[k]))
array[j][k] = array[j][k]/4;
else
array[j][k] = array[j][k] + tempArray[k];
}
}
free(tempArray);
}
int putInvertibleMatrixIntoFile(int n, int** array)
{
FILE* fp = NULL;
int i = 0;
int j = 0;
if((fp = fopen("input","w"))==NULL)
{
printf("Error: writing file error!\n");
return -1;
}
for(i = 0; i < n; ++i)
{
for(j = 0; j < n; ++j)
{
if(j != (n-1))
fprintf(fp,"%d\t", array[i][j]);
else
fprintf(fp,"%d", array[i][j]);
}
fputs("\n",fp);
}
fclose(fp);
return 1;
}gcc -o invertible invertiblematrix.c我们以5*5的矩阵为例试一下
原文：http://blog.csdn.net/liu1075538266/article/details/51484985