'for' loop initial declarations are only allowed in C99 mode

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#include<stdio.h>
#include<math.h>
int main()
{
int n, r;
scanf("%d%d", &n, &r);
float point[n][2];
for(int i = 0; i <= n-1; i ++)
scanf("%f%f", &point[i][0], &point[i][1]);
float output = 0;
for(int i = 1; i <= n-1; i ++)
output = sqrt( (point[i][0]-point[i+1][0])*(point[i][0]-point[i+1][0]) + (point[i][1]-point[i+1][1])*(point[i][1]-point[i+1][1]) )+ output;

output = output + sqrt( (point[n-1][0]-point[0][0])*(point[n-1][0]-point[0][0]) + (point[n-1][1]-point[0][1])*(point[n-1][1]-point[0][1]) );

output = output + 2*acos(-1)*r;
printf("%.2f", output);
return 0;
}