# Banker algorithm program in C for deadlock avoidance

The banker algorithm is developed by Edsger Dijkstra and used for deadlock avoidance by executing processes according to the resources they need. this algorithm is basically testing whether the safe state exists or not.

## C program for bankers algorithm

``````
#include<stdio.h>

int main() {
/* array will store at most 5 process with 3 resoures if your process or
resources is greater than 5 and 3 then increase the size of array */
int p, c, count = 0, i, j, alc, max, need, safe, available, done, terminate = 0;
printf("Enter the number of process and resources");
scanf("%d %d", & p, & c);
// p is process and c is diffrent resources
printf("enter allocation of resource of all process %dx%d matrix", p, c);
for (i = 0; i < p; i++) {
for (j = 0; j < c; j++) {
scanf("%d", & alc[i][j]);
}
}
printf("enter the max resource process required %dx%d matrix", p, c);
for (i = 0; i < p; i++) {
for (j = 0; j < c; j++) {
scanf("%d", & max[i][j]);
}
}
printf("enter the  available resource");
for (i = 0; i < c; i++)
scanf("%d", & available[i]);

printf("\n need resources matrix are\n");
for (i = 0; i < p; i++) {
for (j = 0; j < c; j++) {
need[i][j] = max[i][j] - alc[i][j];
printf("%d\t", need[i][j]);
}
printf("\n");
}
/* once process execute variable done will stop them for again execution */
for (i = 0; i < p; i++) {
done[i] = 0;
}
while (count < p) {
for (i = 0; i < p; i++) {
if (done[i] == 0) {
for (j = 0; j < c; j++) {
if (need[i][j] > available[j])
break;
}
//when need matrix is not greater then available matrix then if j==c will true
if (j == c) {
safe[count] = i;
done[i] = 1;
/* now process get execute release the resources and add them in available resources */
for (j = 0; j < c; j++) {
available[j] += alc[i][j];
}
count++;
terminate = 0;
} else {
terminate++;
}
}
}
if (terminate == (p - 1)) {
printf("safe sequence does not exist");
break;
}

}
if (terminate != (p - 1)) {
printf("\n available resource after completion\n");
for (i = 0; i < c; i++) {
printf("%d\t", available[i]);
}
printf("\n safe sequence are\n");
for (i = 0; i < p; i++) {
printf("p%d\t", safe[i]);
}
}

return 0;
}
``````

## output

```Enter the number of process and resources
5 3
enter allocation of resource of all process 5x3 matrix
0 1 0
2 0 0
3 0 2
2 1 1
0 0 2
enter the max resource process required 5x3 matrix
7 5 3
3 2 2
9 0 2
4 2 2
5 3 3
enter the  available resource 3 3 2

need resources matrix are
7       4       3
1       2       2
6       0       0
2       1       1
5       3       1

available resource after completion
10      5       7
safe sequence are
p1      p3      p4      p0      p2```