Friday, February 13, 2015

C Program for LRU (Last Recently Used) Page replacement technique implementation

#include<stdio.h> #include<conio.h> int n,ref[100],fs,frame[100],count=0; void input(); void show(); void cal(); void main() { printf("****************** LRU Page Replacement Algo *********************\n"); input(); cal(); show(); getch(); } void input() { int i; printf("Enter no of pages in Refrence String\t"); scanf("%d",&n); printf("Enter the reference string:"); for(i=0;i<n;i++) scanf("%d",&ref[i]); printf("Enter the Frame Size\t"); scanf("%d",&fs); } void cal() { int i,j,k=0,c1,c2[100],r,temp[100],t; frame[k]=ref[k]; count++; k++; for(i=1;i<n;i++) { c1=0; for(j=0;j<fs;j++) { if(ref[i]!=frame[j]) c1++; } if(c1==fs) { count++; if(k<fs) { frame[k]=ref[i]; k++; } else { for(r=0;r<fs;r++) { c2[r]=0; for(j=i-1;j<n;j--) { if(frame[r]!=ref[j]) c2[r]++; else break; } } for(r=0;r<fs;r++) temp[r]=c2[r]; for(r=0;r<fs;r++) { for(j=r;j<fs;j++) { if(temp[r]<temp[j]) { t=temp[r]; temp[r]=temp[j]; temp[j]=t; } } } for(r=0;r<fs;r++) { if(c2[r]==temp[0]) frame[r]=ref[i]; } } } } } void show() { printf("Page Faults = %d",count); }


Output:




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